Blacks, Women Less Likely to be Referred for


High-Tech Cardiac Tests, According to Study


By Miguel R. Kamat, MD, MPH


Closing the Gap, Putting the Right People in the Right Places • May/June 1999


Aground-breaking study in the February 25, 1999 issue of the 

New England Journal of Medicine (NEJM), titled, “The Effect of Race and Sex on Physicians’ Recommendations for 

Cardiac Catheterization,” found that Blacks and women with identical complaints of chest pain are less likely than Whites and men respectively to be referred by doctors for sophisticated cardiac tests. 

Since the study tightly controlled for confounding factors such as 

insurance and occupation, symptoms, patient presentation styles and 

physician perceptions of the probability of underlying coronary artery disease, the authors concluded that the different referral rates may 

reflect the presence of race and sex bias on the part of physicians. 

“This study deals with a very serious problem,” said U.S. Surgeon General David Satcher, MD. “It shows that the same problems 

that affect relationships in other segments of society affect the doctorpatient relationship.” 

While there is a growing body of medical literature documenting 

race- and gender-based disparities in health care, this is the first largescale study to focus on whether such differences specifically reflect 

bias in physician clinical decision-making. For instance, a recent review of studies reporting racial differences in health care access and use 

among similarly insured populations by the Office of Minority Health 

found that racial disparities have been reported in a variety of areas, 

including consideration for diagnostic and treatment procedures, patient use of health services, treatment options, and survival rates. These 

disparities have been most thoroughly researched in the use of certain 

cardiovascular diagnostic and treatment procedures. 

“Blacks are 40 percent more likely to die from heart disease than 

Whites,” said Dr. Satcher, commenting on the NEJM study. “And this 

could be one factor.” 

Previous studies have shown that Blacks within the Medicare 

and Veterans Administration insured populations have lower rates of 

certain cardiovascular diagnostic and treatment procedures, even after 

controlling for coexisting conditions, age, supplemental insurance, 

access to hospitals equipped to provide invasive procedures, previous 

diagnostic procedures, and disease severity. Explanations offered for 

these discrepancies included unmeasured clinical or socioeconomic 

factors, willingness of patients to accept referral for surgery, and physician bias. The importance of the NEJM study is that it screened out 

these other variables, leaving only race and gender as the perceived 

differences among patients, which in turn permitted the study to 

exclusively investigate the effect of race/gender bias on the resulting 

physician treatment recommendations. 

In the NEJM study, 720 physicians in full-time clinical practice 

who were attending either of two major national medical meetings 

volunteered to participate in a computerized survey in which they 

were presented with a video recorded interview and other data about 

a hypothetical patient, following which they made recommendations 

for the patient’s management. Six experimental factors, race (Black or 

White), sex, age (55 or 70 years), level of coronary risk (low or high), 

type of chest pain and results of an exercise stress test 

with thalium were utilized to create hypothetical patient presentations, which were simulated by eight actors. In an attempt to control for inter-patient variation in patient 

appearance, style and personality, the actors wore identical hospital 

gowns, used identical styles of presentation of clinical symptoms, and 

even adopted the same angle to the camera during the interviews. 

Simulated patients were given the same insurance and occupations. 

Finally, differences in physician perceptions of the prevalence of clinically significant coronary artery disease based on patient race and sex 

were controlled for by having the physicians estimate in advance the 

probability of the presence of significant disease. 

The study found that the odds of being referred for cardiac 

catheterization were 60 percent less for Blacks than for Whites, 60 

percent less for females than for males, and 40 percent less for Black 

females than for White males. Cardiac catheterization is a test in which 

radio-opaque dye is injected into the coronary arteries supplying blood 

to the heart, in order to make them visible on X-ray images. By looking 

at these images, heart specialists can estimate the degree of coronary 

artery disease, determine whether it presents a danger of heart attack, 

and decide whether to perform preemptive cardiac bypass surgery. 

Since the effects of other variables had been controlled, these findings 

suggest that physician bias affects patient treatment recommendations. However, the study could not assess the form of bias present 

(i.e., whether the prejudice was overt or subconscious). Overt bias 

results from deliberate actions or thoughts, whereas subconscious bias 

results from a cultural stereotype that relates to a patient’s membership 

in a target group, regardless of the level of prejudice the physician may 

have. 

The authors acknowledged two limitations. The physician 

samples may have been nonrepresentative, since physicians attending 

professional meetings may be better informed than their colleagues, 

and volunteers may have had a greater interest in coronary heart disease than non-volunteering clinicians. Secondly, assessments based 

on video recordings may not reflect actual clinical settings as accurately as case vignettes. 

Still, the study is a first of its kind in that it demonstrates that 

physicians bias is a factor responsible for underreferral rates of Blacks 

and women for high-tech cardiac tests in the U.S. Documentation of 

this provider bias should facilitate curriculum review at medical schools 

and residency training programs in order to teach doctors-in-training 

how to explore their own subconscious attitudes toward race and sex. 

Furthermore, the findings of the study may strengthen efforts by 

Congress and the Federal Government to address this issue. 

“I think professional societies, medical schools and educators of 

health professionals at all levels should be involved in helping to 

sensitize and educate physicians and other health professionals about 

this problem,” Dr. Satcher said. 

Indeed, it is timely to focus the spotlight on the existence of 

provider bias as a factor responsible for inequitable access to health 

care in the U.S. and to surmount this obstacle, if all people in the 

Nation are to receive equitable, quality health care. 

Dr. Kamat was a staff fellow (Medical Officer) with 

the Office of Minority Health, U.S. Department of Health 

and Human Services.

Office of Minority Health Resource Center U.S. Department of Health and Human Services